engleski

Reliability of radiological criteria for anticipating a pathological fracture in simple bone cyst of the proximal femur

Purpose Simple bone cyst (SBC) located in a biomechanically unfavourable area such as the proximal femur significantly raises risk of pathological fracture (PF). Various radiological criteria (bone cyst index-BCI, bone cyst diameter-BCD ; minimal cortical thickness-MCT) have been suggested to help predict which cysts will lead to PF. The aim of this study is to evaluate these criteria. Methods Twenty-six patients treated at our department from 1981 to 2008 for proximal femoral SBC were divided into two groups, with presence of PF at presentation being the difference between groups. Pertinent radiological criteria were measured (BCI, BCD-longitudinal and transversal, MCT-medial and lateral) on plain radiographs. Results Average age of the patients was 10.6 years (range 3–20 years). Diagnosis of proximal femoral SBC was confirmed in all patients. Group A consisted of 12 (9 male, 3 female) patients who presented with PF through the proximal femoral SBC. Median BCI was 4.19 (IQR 3.08, Q1 2.96, Q3 6.04). Median BCD (mm) longitudinally was 48.15 (IQR 34.2, Q1 37.8, Q3 72), transversely 27 (IQR 15.75, Q1 23.4, Q3 39.15). Median MCT (mm) medially was 1.8 (IQR 1.4, Q1 0.9, Q3 2.3), laterally 1.8 (IQR 1.8, Q1 0.9, Q3 2.7). Group B included 14 (12 male, 2 female) patients without PF through proximal femoral SBC at presentation. Median BCI was 4.26 (IQR 2.85, Q1 2.83, Q3 5.68). Median BCD (mm) longitudinally was 54.9 (IQR 34.2, Q1 42.3, Q3 76.5), transversely 29.2 (IQR 14.4, Q1 21.6, Q3 36). Median MCT (mm) medially was 1.8 (IQR 1.8, Q1 0.9, Q3 2.7), laterally 1.8 (IQR 0.9, Q1 0.9, Q3 1.8). Conclusions No significant differences of measured values were found between the two groups. The proposed radiological criteria are not reliable to anticipate occurrence of PF through SBC. Significance Ability to predict PFs using simple radiological criteria would help lower the considerable morbidity they cause.

bone cyst ; proximal femur ; Pathological fracture ; radiography

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